Diabetes mellitus and its chronic complications have seriously affected the healthy and life quality of human being. The number of patient has increased in recent years and the attack rate of diabetic nephropathy in every age group is 2.8% in 2000 when in 2030 is predicted to be 4.4% all around the world, which means that the number of diabetic patient will increase from 1.71 hundred millions in 2000 to 3.33 hundred million in 2030. With the increasing attack rate every year, the quantities of patients in China has been second only India. Therefore, the prevention and cure of diabetic and its complications has been a very important topic these days. Diabetic nephropathy (DN), one of the important complications of diabetic, has been the first place of diseases which leads to the final stage of renal failure. As shown by the data of world health organization that about 30% of I type and 25%-40% II type diabetic patients would improve to be DN patients if the blood glucose was not controlled. Because of delitescence and difficult to discover of DN in earlier period, it will can not be reverse when the symptom of renal affection appears. The yearlong diabetic can destroy filtration function of renal and express as microamount albuminuria. With the extend of disease course, albuminuria will increase and the ability of renal for eliminating toxin in blood decays gradually, which leads to the end stage renal disease (ESRD) and the patients can only maintain their life by hematodialysis or kidney transplant. Thereby, it is badly need to deeply elucidate the mechanism of DN, rich and consummate the measures of prevention and cure.
Advanced glycation end products (AGES) is a covalence conjugate of macromolecule and glyc-carbonyl without catalysis of enzyme. Under the condition of catalysis of non-enzyme, firstly the reversible Schiffs base is formed by free aldehyde of amylaccum molecule and amino group of protein, secondary stationary ketoamine compounds (Amadori products) are formed by the structural rearrangement of Schiffs base, then the stationary and nonreversible AGEs are formed after the reactions of dehydration, oxidation and condensation. AGEs relates closely to the complication of diabetic because it is casy to form the cross-linking agent with the biomacromolecule of protein, nucleic acid, lipide and so on, and then deposit in cells, interfere the normal functions of cell. The interactions of AGEs and RAGE, which lead to produce or activate of many cytokines of proinflammatory factor and profibrosis factor, and lead to the patho-changes of cell hypertrophia, base material accrementition and fibrosis of glomcrulus, take great effect on the generation and development of diabetic nephropathy and is one of the etiological factors. Therefore, intervention of the formation of AGES, elimination of the AGEs had formatted and amendment of the renal disease symptom induced by AGEs can prevent and cure the DN (Bohlender J M, Franke S, Stein G, et al. Advanced glycation end products and the kidney. Am J Physiol Renal Physiol, 2005, 289(4): 645-659).
Cortex Mori, the dry root cortex of Morus alba L., tastes sweet, frigidity and possesses the functions of removing heat from lung and relieving asthima, inducing diuresis to alleviate edema. Cortex Mori is usually used for dyspnea and cough due to lung-heat, oliguria due to dropsy and turg, puffiness of face muscle and skin. The recent pharmacology researches showed that the Cortex Mori possessed the activities of lowering blood sugar and blood pressure, diuresis, preventing cough and relieving asthima, anti-HIV, anti-tumor and so on. Since the active ingredients of 1-deoxynojirimycin and moran A for lowering blood sugar were isolated from Cortex Mori, more and more scholars are looking for new active ingredients of lowering blood sugar from Cortex Mori and next to improve a new drug for diabetic. DPMC is a new natural produce which is first time isolated from the extract of Cortex Mori and the synthetics produce of DPMC used only in chemical engineering field before is to prepare Diphenylmethane diisocyanate (MDI) which is the main material of polyurethane. Up till now, few of domestic or overseas literatures have been reported about the DPMC used in medical field.